NOTE: The newly published paper in the Journal of Applied Toxicology can be
found here:
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Genetically engineered maize: New indication of health risks
Test Biotech & CRIIGEN, 17 February 2012
http://www.testbiotech.org/en/node/620
*Bt protein toxic to human cells
Caen/ Munich - Insecticidal Bt toxins such as those produced in genetically
engineered plants can be detrimental to human cells. This is a result of recent
research led by researchers at the University of Caen (France). Their
experiments showed that toxins produced in, for example, the genetically
engineered maize MON810, can significantly impact the viability of human cells.
The effects were observed with relatively high concentrations of the toxins,
nevertheless there is cause for concern.
For the first time, experiments have now shown that they can have an toxic
effect to human cells. According to companies like Monsanto, which produces
genetically engineered maize with these toxins, the toxins are supposed to be
active only against particular insects and should have no effect on mammals and
humans at all. The investigation of effects of Bt toxins on human cells is not a
requirement for risk assessment in Europe or in any other region
Another finding of the researchers concerns a herbicide formulation sold under
the brand name Roundup. Massive amounts of this herbicide are sprayed on
genetically engineered soybean crops and its residues can be found in food and
feed. According to the new publication, even extremely low dosages of Roundup
(glyphosate formulations) can damage human cells. These findings are in
accordance with several other investigations highlighting unexpected health
risks associated with glyphosate preparations.
"We were very much surprised by our findings. Until now, it has been thought
almost impossible for Bt proteins to be toxic to human cells. Now further
investigations have to be conducted to find out how these toxins impact the
cells and if combinatorial effects with other compounds in the food and feed
chain have to be taken into account," says Gilles-Eric Séralini from the
University of Caen, who supervised the experiments. "In conclusion, these
experiments show that the risks of Bt toxins and of Roundup have been
underestimated."
Bt toxins and tolerance to herbicides are broadly used in genetically engineered
plants. Bt proteins only naturally occur in soil bacteria. By introducing the
modified toxin gene into the plants, the structure of the toxins is modified and
may thereby cause selectivity to be changed. The content of the proteins within
the plants is highly variable. Many genetically engineered plants contain
several Bt toxins at the same time. For example, SmartStax produces six
different Bt toxins and therefore has a higher overall content of the proteins.
In addition, it was made tolerant to herbicides. So far, there has been no
investigation of the combinatorial effects of these toxins and residues from
spraying, or their potential risks for human health, which was considered
unlikely. The researchers have now shown that interactivity does occur. Under
the specific conditions of their experiment, the Bt toxin lowered the toxicity
of Roundup. Further investigations are necessary to examine other
potential combinatorial effects under varying conditions.
"These results are pretty worrying. Risk assessment requirements for genetically
engineered plants and pesticides need to be rigidly enforced. In the light of
these findings, we think that the commercialisation of these plants is not in
accordance with EU regulations", says Christoph Then at Testbiotech. Testbiotech
is closely following risk assessment at the European Food Safety Authority EFSA
and has repeatedly brought attention to gaps in risk assessment.
The research was supported by GEKKO foundation (Germany). CRIIGEN Association
(France) and Testbiotech (Germany) were involved in planning the experiments and
the discussion of results. Findings were published after peer review process.
Mesnage R., Clair E., Gress S., Then C., Székács A., Séralini G.-E., 2012,
Cytotoxicity on human cells of Cry1Ab and Cry1Ac Bt insecticidal toxins alone or
with a glyphosate-based herbicide, Journal of Applied Toxicology,
Contact:
Professor Gilles-Eric Séralini, France: Tel. +33 2 31 56 54 89,
criigen@unicaen.fr
www.criigen.org
Christoph Then, Testbiotech, Germany: +49.15154638040, info@testbiotech.org,
www.testbiotech.org
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